Showing papers by "Montreal Children's Hospital published in 1977"
TL;DR: Caffeine is an effective pharmacologic respirogenic agent in the preterm infant with apnea and all infants except one showed a significant decrease in the frequency of apneic episodes associated with caffeine therapy.
248 citations
TL;DR: Comparisons between classrooms with hyperactive and control children suggested that the presence of a hyperactive child may influence interaction patterns between the teacher and the class as a whole.
Abstract: Summary
Hyperactive and control children, originally observed in a research nursery at age 4 and then followed-up at 6 1/2, were observed in their elementary school classrooms at 7 1/2. Hyperactive children received more negative feedback from teachers, engaged in more disruptive behaviour, were rated by their teachers as more hyperactive, and expressed somewhat lower self-esteem than controls. However, comparisons between classrooms with hyperactive and control children suggested that the presence of a hyperactive child may influence interaction patterns between the teacher and the class as a whole. Moreover, observer presence influenced teachers' positive behaviours toward the child being observed.
135 citations
92 citations
TL;DR: The elevated Viso V in the RDS group suggests an increase in small airway resistance secondary to the disease or to its therapy, and the volumes of iso-flow were higher in the survivors of RDS than those of the children born at term.
89 citations
TL;DR: This review emphasizes the need for routine measurement of serum electrolytes during all phases of the leukemic process, and includes newly diagnosed patients who may show elevated serum potassium, phosphorus, and magnesium--a result of their release from malignant cells after cytotoxic therapy or their accumulation due to urate nephropathy.
75 citations
TL;DR: It is proposed that some process regulates the distribution of phosphorus between serum and bone, and that this process is affected in different ways in HBD and XLH.
Abstract: We have identified 5 patients with a condition which we call hypophosphatemic bone disease (HBD). The clinical findings, appearing during late infancy include modest shortening of stature, bowing of the lower limbs, and nonrachitic bone changes. The concentrations of calcium, parathyroid hormone (PTH), and vitamin D in serum and the basal excretion of cyclic AMP in urine are all normal. The serum phosphorus level is constantly depressed; inpaired reclamation of phosphate anion by kidneys explains this finding.
Net tubular reabsorption of phosphate anion is “normal” at the low endogenous levels of filtered phosphate anion, yet below normal at elevated levels. The phosphaturic response to PTH infusion is abnormal in qualitative aspects. The characteristics of phosphate transport by kidney in HBD differ considerably from those described in X-linked hypophosphatemia (XLH). The transport defect is not expressed in the (non-epithelial) membrane of the erythrocyte.
Since the severity of bone disease is quite different in HBD and XLH, and yet serum (extracellular) phosphorus concentration is similarly low in both diseases, we propose that some process regulates the distribution of phosphorus between serum and bone, and that this process is affected in different ways in HBD and XLH.
In 2 pedigrees HBD is autosomal dominant with variable expression; the mode of inheritance is indeterminate in the other 3 families. The dominantly inherited hypophosphatemia is responsive to 1α OH analogues of vitamin D3.
There is presumptive evidence from the pedigree studies, and in the response to vitamin D analogues, that HBD is not a single entity.
69 citations
TL;DR: It is proposed that the model is highly suited to the study of factors affecting hormonogenesis by the human placenta whether they be of maternal or of fetal origin.
68 citations
TL;DR: Twenty hyperactive children and 21 controls, studied in a research nursery at age four, were followed up at six-and-a-half, and hyperactives were still reported to have more behavior problems and make more immature moral judgments.
Abstract: Twenty hyperactive children and 21 controls, studied in a research nursery at age four, were followed up at six-and-a-half. Hyperactives were still reported to have more behavior problems. Those rated extremely active in the nursery requested more feedback and made more comments in interactions with their mothers, and also made more immature moral judgments; children rated only moderately active did not differ from controls on these measures.
50 citations
TL;DR: The clinical and radiologic features of eight children in six kindreds with onset of the adult-type polycystic renal disease with onset in childhood in the first decade of life are described.
48 citations
TL;DR: Four cases of massive infantile nephroblastomatosis with up to three and one‐half years follow‐up with great similarity was found clinically, radiologically and pathologically, which distinguishes this entity from true Wilms' tumor.
Abstract: Four cases of massive infantile nephroblastomatosis with up to three and one-half years follow-up are described. Great similarity was found clinically, radiologically and pathologically, which distinguishes this entity from true Wilms' tumor. The course of the renal lesion following treatment was monitored by sequential radiological and biopsy studies. The pathogenesis, natural history, and management are discussed.
42 citations
TL;DR: This subgroup of patients with pulmonary atresia with an intact ventricular septum should have a systemic-pulmonary shunt followed later by reconstruction of the right ventricular outflow tract, according to a reasonable passageway formed from right ventricle to pulmonary artery.
TL;DR: Kinetic experiments suggest the presence of an enzyme-activator complex and the dissociation constant of this complex is decreased when higher concentrations of substrate are used, suggesting the formation of a ternary complex between enzyme, activator and substrate.
Abstract: Human liver extracts contain an activating protein which is required for hexosaminidase A-catalysed hydrolysis of the N-acetylgalactosaminyl linkage of G(M2) ganglioside [N-acetylgalactosaminyl-(N-acetylneuraminyl) galactosylglucosylceramide]. A partially purified preparation of human liver hexosaminidase A that is substantially free of G(M2) ganglioside hydrolase activity is used to assay the activating protein. The proceudres of heat and alcohol denaturation, ion-exchange chromatography and gel filtration were used to purify the activating protein over 100-fold from crude human liver extracts. When the purified activating protein is analysed by polyacrylamide-gel disc electrophoresis, two closely migrating protein bands are seen. When purified activating protein is used to reconstitute the G(M2) ganglioside hydrolase activity, the rate of reaction is proportional to the amount of hexosaminidase A used. The activation is specific for G(M2) ganglioside and and hexosaminidase A. The activating protein did not stimulate hydrolysis of asialo-G(M2) ganglioside by either hexosaminidase A or B. Hexosaminidase B did not catalyse hydrolysis of G(M2) ganglioside with or without the activator. Kinetic experiments suggest the presence of an enzyme-activator complex. The dissociation constant of this complex is decreased when higher concentrations of substrate are used, suggesting the formation of a ternary complex between enzyme, activator and substrate. Determination of the molecular weight of the activating protein by gel-filtration and sedimentation-velocity methods gave values of 36000 and 39000 respectively.
TL;DR: Agar dilution antimicrobial susceptibility tests were carried out against recent clinical isolates of Yersinia enterocolitica biotype 4, serotype O:3, and all isolates were resistant to ampicillin, carbenicillin, cloxacillin, and erythromycin.
Abstract: Agar dilution antimicrobial susceptibility tests were carried out against recent clinical isolates of Yersinia enterocolitica biotype 4, serotype O:3. Aminoglycosides and co-trimoxazole were the most active drugs. All isolates were resistant to ampicillin, carbenicillin, cloxacillin, and erythromycin.
TL;DR: Preliminary evidence indicates that a silylated derivative of oxidized DTT can be detected in the urine of patients receiving DTT by mouth, which suggests that the thiol is absorbed and excreted.
Abstract: Summary: Two male patients with late stage (uremic) infantile nephropathic cystinosis (INC) (Table 1) were treated by mouth with the reducing agent dithiothreitol (DTT), at doses not exceeding 25 mg-kg-1 body weight three times per day. Three sequential periods of observation were obtained in both patients: on thiol (8.5 months); off thiol (8–9 months); on thiol again (7 months or longer). Other than nausea and vomiting at the maximum dose range, no apparent toxicity was observed. One subject died in uremia in the 24th month of the study. The half-cystine concentration in peripheral blood leukocytes decreased during both treatment periods in each patient from initial pretreatment levels in excess of 8 nmol·mg-1 protein (normal <0.1 nmol mg-1) to 10–20% of initial values (Table 2 and Fig. 1, A and B). Reduction in total number of blood leukocytes or in the neutrophil fraction, where cystine storage occurs selectively in cystinosis, did not occur (Table 3) as a possible explanation for these findings; nor did storage of samples, a possible artifact, influence the cystine content of cystinotic cells (Fig. 2). Multiple site rectal mucosa biopsy clearly revealed cystine storage but serial biopsies did not reflect a positive DTT response when compared with the leukocyte assay (Table 4). High intersample variation in cystine content, even between samples taken at one time, prevented measurement of a treatment response. DTT had no apparent detrimental effect on the concentration of representative proteins, including hemoglobin (Table 3), serum insulin, and serum immunoglobulin during the treatment trials. Renal function (glomerular and tubular) was severely depressed and did not improve during the period of observation in either patient (Table 2; Fig. 3, A and B). Postmortem tissues from one patient revealed 10–40-fold excess cystine accumulation in kidney cortex and liver (Table 5). However, these levels of accumulation are at the lower range of or even below published values for cystine in cystinotic kidney and liver. Whereas chemical methods are not reliable for detecting and measuring DTT in biologic fluids, preliminary evidence indicates that a silylated derivative of oxidized DTT can be detected in the urine of patients receiving DTT by mouth (Fig. 4). This finding suggests that the thiol is absorbed and excreted. Speculation: The defect in cystine metabolism (or transport) in cystinosis remains unknown. However, if administered early in the course of INC, DTT might prevent the occurrence of irreversible phenotypic components by preventing cystine accumulation.
TL;DR: The data show that a loading dose of 10 mg/kg of caffeine achieves a peak plasma concentration (Cp) of 8 to 14 mg/L, which makes monitoring of Cp mandatory during maintenance therapy for apnea.
Abstract: The newborn infant is exposed to caffeine either transplacentally or postnatally for the treatment of apnea. Using a one-compartment model, the pharmacokinetic disposition of caffeine in the neonate was determined. Caffeine (as the citrate salt) was given to 10 premature infants with apnea at a dose of 5 to 20 mg/kg via intravenous infusion for 10 to 20 min. Caffeine was measured in 10 μl of plasma by radioimmunoassay (Cook, Research Triangle Park, N.C). Blood samples were obtained by heelsticks at 2 to 8h interval for 72 to 86h. Relative to adult whose T4 is 3 to 5h, caffeine was eliminated slowly. Neither AVd, T4, kel nor clearance correlated with birth weight or postnatal, gestational or postconceptional age. The data show that a loading dose of 10 mg/kg of caffeine (or 20 mg/kg of caffeine citrate) achieves a peak plasma concentration (Cp) of 8 to 14 mg/L. Maintenance dose of 2.2 mg/kg/24 h maintained Cp of 10 mg/L. The 7-fold range of individual caffeine clearance makes monitoring of Cp mandatory during maintenance therapy for apnea.
TL;DR: A case of infantile metastasizing Wilms' tumor is described clinically and pathologically and the unusual pattern of clinical presentation and metastases is emphasized as it may be characteristic for this rare entity.
Abstract: A case of infantile metastasizing Wilms' tumor is described clinically and pathologically. The presenting feature was congenital hydrocephalus due to cerebral metastases. The literature is reviewed and four similar examples are found. The unusual pattern of clinical presentation and metastases is emphasized as it may be characteristic for this rare entity.
TL;DR: It is concluded that caffeine markedly potentiates the effect on inspiratory drive, and the therapeutic efficacy of caffeine in apnea is best explained by increase in inspiratory center output.
Abstract: Caffeine is used in the treatment of apnea in low-birth-weight infants despite inadequate data on the physiological basis for its efficacy. The effect of increasing doses of caffeine (10-70mg/kg) on pulmonary ventilation (VE) mean inspiratory flow (VT/TI) and tracheal pressure generated at 0.5 sec (P0.5) after the onset of inspirations against occluded airways at functional residual capacity was studied in pentobarbital (35mg/kg) anesthetized cats, breathing various gaa mixtures under steady state conditions. During room air and 50% O2 breathing (balance N2), increasing doses of caffeine caused a progressive increase in VE with corresponding increase in P0.5 snd VT/TI without changing TI/Ttot (ratio of inspiratory time to total cycle duration) indicating that caffeine primarily affects inspiratory drive. Increasing doses of caffeine also caused an incremental decrease in end-tidal PCO2, causing & negative feedback on inspiratory center drive. When PCO2 was maintained at control (pre-caffeine) levels, the increase in OE, VT/TI and P0.5 at all caffeine levels, was sbout 3-fold greater tnan non-iso- CO2 conditions. Thus, the concomitant hypocapnia greatly masked the inspiratory drive by caffeine. We conclude that caffeine markedly potentiates the effect on inspiratory drive. The therapeutic efficacy of caffeine in apnea is best explained by increase in inspiratory center output.
TL;DR: Application of this screening method to 260 adult subjects at risk for thalassaemia heterozygosity yielded an unbiased frequency of 0.067 for the adult carrier in the Montreal Greek community, a value similar to that reported in the source population in Greece.
Abstract: Seven red cell parameters, taken one at a time and in their 21 possible pairs, were investigated for their power to discriminate between adult carriers of the β-thalassaemia allele and adult normal subjects. The red blood cell count (RBC), haemoglobin concentration (Hb), haematocrit (Hct), mean cell volume (MCV), mean cell haemoglobin (MCH), mean cell haemoglobin concentration (MCHC), and haemoglobin A2(HbA2) fraction were measured in 24 obligate heterozygotes and in 99 adult controls with comparable age and sex distributions. Quadratic discriminant functions were computed using Bayesian analysis of univariate and bivariate Gaussian density functions. Classification errors were then calculated by integrating the density function for one genotype over the region assigned to the other. In the univariate case, MCH led to the lowest cost of misclassification while MCV was the second best discriminant for all posterior probabilities considered. In the bivariate case, MCV combined with percentage Hb A2 yielded the best discrimination and generated misclassification costs roughly 1/30 of those generated by the most efficient single parameter. When use of MCV alone cannot classify an individual reliably either as a heterozygote or as homozygous normal, combined use of MCV and percentage Hb A2 is recommended for maximum accuracy. Application of this screening method to 260 adult subjects at risk for thalassaemia heterozygosity yielded an unbiased frequency of 0.067 for the adult carrier in the Montreal Greek community, a value similar to that reported in the source population in Greece. The improved discriminations thus achieved is particularly useful for sibs of affected subjects whose high prior probability of heterozygosity (0.67) impairs classification.
TL;DR: The clinical example presented by the author is a description of the assessment and treatment of a four-year-old boy who had been mauled by a leopard in a suburban pet store and the fact that conflicts predated the traumatic event is postulated to be a determinant of the traumatic process.
Abstract: In the introduction to a clinical example of a young boy with a traumatic neurosis, this paper reviews the phenomena of psychic trauma. Freud's contribution to the initial description of the phenom...
TL;DR: This radioisotope method has been used to identify cells with biochemical lesions in the oxidation of propionate, galactose, hypoxanthine and pyruvate and has allowed us to identify a new variant of methylmalonicaciduria and it is believed it can be extended to include other metabolites and pathways.
TL;DR: It is suggested that spasticity could be alleviated by administration of the vitamin B 6 antagonist aminooxyacetic acid (AOA), suggesting that the primary defect in the spastic mouse is in the metabolism of a neurotransmitter.
Abstract: Mice that are homozygous for the spa gene (Chai, 1961) exhibit a number of neurological defects of which the most striking is impaired ability to right themselves when turned over on their backs. Chai et al. (1962) tound that spasticity could be alleviated by administration of the vitamin B 6 antagonist aminooxyacetic acid (AOA), suggesting that the primary defect in the spastic mouse is in the metabolism of a neurotransmitter. Six neurotransmitters are metabolized by pyridoxal phosphate (PLP) dependent enzymes (Clark, 1963). Furthermore, the anticonvulsant activity of AOA has been described in rats (DaVanzo et al., 1961), mice (Bushnel and Lehman, 1963), and dogs (Essig, 1963). In vivo, AOA preferentially inhibits 7-aminobutyric acid transaminase (GABA-T) (Baxter and Roberts, 1961), causing up to fourto fivefold elevation of brain GABA (Wood and Peesker, 1975). An attractive hypothesis concerning the nature of the metabolic defect in spastic mice is that GABA concentration is lowered because of either a decrease in its rate of formation or an increase in the rate of breakdown. Chai et al. (1962), however, were not able to detect differences in the total brain concentration of GABA between spastic mice and normal littermates.
TL;DR: It is concluded that at midpregnancy the regulation of corticoidogenesis implies the existence of a corticotrophic factor either identical or closely related to ACTH.
TL;DR: From the Department of Pediatric Surgery, Montreal Children’s Hospital, cholecystitis and cholelithiasis are almost exclusively diseases of older patients.
Abstract: From the Department of Pediatric Surgery, Montreal Children’s Hospital. * Montreal Children’s Hospital, 2300 Tupper Street, Montreal, Quebec, H3H 1P3, Canada (reprint requests). t Department of Surgery and Pediatrics, University of Florida Medical Center, Gainesville, Fla. 32610. IT IS TRADITIONAL BELIEF that cholecystitis and cholelithiasis are almost exclusively diseases of older patients. Because off
01 Jan 1977
TL;DR: My contribution to the mix is a chapter on strategies about enzyme replacement therapy; other authors provide the tactical details upon which the successful campaign for such treatment will depend.
Abstract: A nursery rhyme, which some of us learned when we were children brought tinker, tailor, soldier, and sailor together (Opie and Opie, 1951), rather like this volume, where its authors have been convened from many disciplines to describe how the diverse indexes of our individuality—our proteins—can be handled for biomedical purposes. My contribution to the mix is a chapter on strategies about enzyme replacement therapy; other authors provide the tactical details upon which the successful campaign for such treatment will depend.
TL;DR: No abnormalities could be defined in red blood cell carbonic anhydrase activity in three patients with renal tubular acidosis, two of whom were deaf.
Abstract: Summary: Red blood cell carbonic anhydrase activity was studied in three children with distal renal tubular acidosis, the parents of one of these patients, and in control subjects. Although each patient had distal renal tubular acidosis as defined by an inappropriately high urine pH in the face of a systemic metabolic acidosis, hyperchloremia and a low (U-B)pCO2, they differed in that two had deafness. The deafness was inherited as an autosomal recessive mode in one and by an autosomal dominant gene in the other. Red blood cell carbonic anhydrase activity was determined in hemoglobin-free hemolysate by the esterolytic action of the enzyme on the substrate p-nitrophenyl acetate. The two isoenzymes, B and C, of carbonic anhydrase were identified using polyacrylamide disc gel electrophoresis. The red blood cell carbonic anhydrase activity of nine control children aged 2–10 years was 3.8 (3.2–5.0) units/g Hb. The values obtained from the three patients were 3.0, 3.7, and 4.36 units/g Hb. These did not differ from those of the control subjects. No abnormalities were found in the ratios of the B and C peaks or in their electrophoretic mobility. Speculation: Although carbonic anhydrase appears to have an important role in the acidification of the urine, and although an abnormality in red blood cell carbonic anhydrase has been described in a patient with renal tubular acidosis and deafness, no abnormalities could be defined in red blood cell carbonic anhydrase activity in our three patients with renal tubular acidosis, two of whom were deaf.
TL;DR: The results are discussed in terms of the localization of D-AAO in cell types especially sensitive to thyroid hormone: a cell type which is among the last to derive from the external germinal zone in the developing cerebellum, and which in the adult is located adjacent to the Purkinje cell soma.
TL;DR: Neonatal screening of over 200,000 Infants in Québec by filter paper spot T4 and TSH determinations has detected congenital hypothyroldism and data suggest that a minimum T4 dose is required to maintain serum T4 above 10 ug/dl and serum TSH below 15 uU/ml.
Abstract: Neonatal screening of over 200,000 Infants in Quebec by filter paper spot T4 and TSH determinations has detected congenital hypothyroidism in 1/6,000 live births (85% primary). Hypothyrold infants were immediately started on combined L-thyroxine (T4), 25ug daily, and L-trilodothyronine (T3), 5ug TID for 2 wks when the T3 was discontinued and the T4 was increased to 50ug daily. Thereafter the dosage of T4 was adjusted according to serum levels of T4 and TSH or clinically. Serum hormone levels were determined after 2 & 6 wks of therapy, and then every 3 months of age. Results are: These data suggest that a minimum T4 dose of 5 ug/kg/day (2.5 times the dose recommended in adult acquired hypothyroldism and 50% that usually recommended for infants) is required to maintain serum T4 above 10 ug/dl and serum TSH below 15 uU/ml. No serious toxicity has developed with this regimen and early clinical progress has been satisfactory.
TL;DR: A new assay for proteolytic enzymes and their inhibitors based on the liquefaction of gelatin gels has been developed, which is more sensitive than colorimetric tests, can be carried out upon colored or turbid samples and does not require the use of a spectrophotometer.